Getting directly to the point i think there should be more building sets that help building in the Frozen North.
Currently the two build sets that allow for it are Black Ice and Khitan.
rather than the introduction of a whole new set for it i would suggest that Frontier be converted to Cold as i personally think it suits the Frozen north more than a desert environment.
additionally, i think these buildings should be built with Insulated wood rather than Hardened brick to make them a viable alternative to the Black Ice.
finally, make these temperature buffs more significant. this to prevent Black Ice building in the desert where it does not belong. these buffs will help a player in the frozen north survive within their base even while unarmored while causing a player in the desert that builds with Black ice overheat unless steps are taken